Recently, a novel ultrasonic fat reduction technology emerges in the world. A focused ultrasonic wave with a frequency of about 500 kHz is continuously transmitted to a patient transcutaneously via a hand-held ultrasonic transducer. The ultrasonic wave passes through the skin and reaches the underlying adipose layer. The structure of fat cells is destroyed by the physical effects such as thermal effect, high sound pressure due to the ultrasonic wave, so as to free the lipid contents included therein. The free lipid, after a period of time, is absorbed via the body's own metabolism, thereby to achieve a fat reduction and body shaping effect. However, the speed of treatment is restrained because the aforementioned hand-held ultrasonic transducer is operated with great complexity and effort, and inconvenient to assemble and disassemble a treatment head.